Device for controlling the relative rotary position between a crankshaft and a camshaft

Abstract

In a device for controlling the relative rotary positions of a crankshaft and a camshaft of an internal combustion engine, a drive wheel is connected to the camshaft by way of an angular position control mechanism including a planetary gear arrangement with an annular gear connected to, or part of, the drive wheel, a sun gear mounted on the camshaft and at least one planetary gear disposed between, and in engagement with, the annular gear and the sun gear and rotatably supported on a planetary gear carrier, which is rotatable over a certain angular range by a stationary servomotor for controlling the angular positions of the camshaft relative to the crankshaft.

What is claimed is:  
     
         1 . A device for controlling the relative rotary positions of a crankshaft and a camshaft of an internal combustion engine comprising a drive wheel connected to said camshaft by way of an angular position control mechanism including a planetary gear arrangement having an annular gear rotatable with said drive wheel, a sun gear mounted within said annular gear, and in radially spaced relationship therefrom, on said camshaft for rotation with said camshaft, a planet carrier supported so as to be rotatable about the camshaft axis, at least one planetary gear supported on said planet carrier and being disposed in the space between, and in engagement with, said annular gear and said sun gear, and a servomotor including an actuating gear mechanism engaging said planet carrier for rotating said planet carrier over a predetermined angular range for controlling the angular position of said camshaft relative to said crankshaft.  
     
     
         2 . A device according to  claim 1 , wherein said planetary gear mechanism has a step-down transmission ratio (i 2 ) from the ring gear to the sun gear which is greater than 1.  
     
     
         3 . A device according to  claim 1 , wherein said drive wheel and said annular gear are an integral part.  
     
     
         4 . A device according to  claim 1 , wherein said actuating gear mechanism includes a plurality of gear stages.  
     
     
         5 . A device according to  claim 1 , wherein said actuating gear mechanism includes a circumferentially toothed gear wheel, which is in engagement with said planet carrier and is driven by a pinion which is mounted on the shaft of the servomotor.  
     
     
         6 . A device according to  claim 1 , wherein the actuating gear mechanism includes a worm gear drive consisting of a helical gear connected to the planet carrier and a worm connected to the shaft of the servomotor.  
     
     
         7 . A device according to  claim 6 , wherein said helical gear is formed directly on said planet carrier.  
     
     
         8 . A device according to  claim 1 , wherein the servomotor includes a spring-loaded motor brake, which engages, when said service motor is de-energized.  
     
     
         9 . A device according to  claim 1 , wherein the actuator gear mechanism is a self-locking arrangement.  
     
     
         10 . A device according to  claim 1 , wherein the gear mechanism driving said planetary carrier is loaded by a pre-stressed spring element in a direction for accommodating a reaction torque effective on said planet carrier.  
     
     
         11 . A device according to  claim 1 , wherein the servomotor comprises a control unit, which controls the adjustment of the camshaft as a function of characteristic operating values of the internal combustion engine.